As a sliding operation type electric part, heretofore there is known a part, in which a plurality of electric controls are effected by displacing an operation level. For example, a lightening type sliding variable resistance is a part, in which the value of a resistance and the on and off of light emitting diodes are controlled by displacement of one operation lever and which is used for graphic equalizer.
Such a prior art lightening type sliding variable resistance is generally so constructed that a resistor and a collector for the variable resistance and a collector for the light switch are disposed in parallel on a base plate and sliders sliding on conductive patterns are disposed on the lower surface of a slider holder, whereby the contact position of the slider with each of the conductive patterns is varied by operating an operation lever projectingly disposed on the upper surface of this slider holder.
However such a prior art lightening type sliding variable resistance has drawbacks that, since the conductive patterns and the sliders, which are slidingly in contact therewith, are disposed in parallel, it is large in the width and that in the field of the control of parts, since the form of the slider is complicated, they are easily deformed at the mounting, the transportation, etc.
In order to remove these drawbacks, a new lightening type sliding variable resistance has been proposed, as disclosed in JP-Utility Model-A-59-195701, in which a plurality of conductive patterns are disposed, divided into two groups, one on a base plate and the other in a case located thereon, at the same time, corresponding to these conductive patterns, the slider, which is slidingly in contact with the collector for the light switch, is disposed on the upper surface of the slider holder and the slider, which is slidingly in contact with the resistor and the collector for the variable resistance, is disposed on the lower surface of the slider holder.
According to the prior utility model application stated above disclosing the sliding operation type electric part, since a plurality of conductive patterns are divided into two groups, upper and lower, it is possible to make it smaller and in particular to make the size in the direction of the width considerably smaller. However, since it is necessary to dispose the sliders, which are slidingly in contact with the conductive patterns, on both the upper and lower surfaces of the slider holder, it is very difficult because of the structure of the metal mold to adopt a method for forming sliders and a slider holder in one body, which has been developed for the purpose of increasing the productivity, i.e. a method, by which the slide holder is formed by insert in the sliders to unite them in one body. For this reason it was inevitable to adopt a structure, in which pins disposed projectingly on the slider holder are inserted in holes formed in the sliders and they are fixed to each other by calking. This structure has drawbacks in productivity and in work efficiency.